From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-f70.google.com (mail-io1-f70.google.com [209.85.166.70]) by kanga.kvack.org (Postfix) with ESMTP id 18D8B6B0005 for ; Tue, 9 Oct 2018 08:52:34 -0400 (EDT) Received: by mail-io1-f70.google.com with SMTP id f5-v6so1210591ioq.17 for ; Tue, 09 Oct 2018 05:52:34 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id p14-v6si14806058jap.74.2018.10.09.05.52.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Oct 2018 05:52:32 -0700 (PDT) Subject: Re: [PATCH] mm, oom_adj: avoid meaningless loop to find processes sharing mm References: <67eedc4c-7afa-e845-6c88-9716fd820de6@i-love.sakura.ne.jp> <20181008011931epcms1p82dd01b7e5c067ea99946418bc97de46a@epcms1p8> <20181008061407epcms1p519703ae6373a770160c8f912c7aa9521@epcms1p5> <20181008083855epcms1p20e691e5a001f3b94b267997c24e91128@epcms1p2> <20181009063541.GB8528@dhcp22.suse.cz> <20181009075015.GC8528@dhcp22.suse.cz> <20181009111005.GK8528@dhcp22.suse.cz> From: Tetsuo Handa Message-ID: <99008444-b6b1-efc9-8670-f3eac4d2305f@i-love.sakura.ne.jp> Date: Tue, 9 Oct 2018 21:52:12 +0900 MIME-Version: 1.0 In-Reply-To: <20181009111005.GK8528@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: ytk.lee@samsung.com, "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Oleg Nesterov , David Rientjes , Vladimir Davydov , Andrew Morton , Linus Torvalds On 2018/10/09 20:10, Michal Hocko wrote: > On Tue 09-10-18 19:00:44, Tetsuo Handa wrote: >>> 2) add OOM_SCORE_ADJ_MIN and do not kill tasks sharing mm and do not >>> reap the mm in the rare case of the race. >> >> That is no problem. The mistake we made in 4.6 was that we updated oom_score_adj >> to -1000 (and allowed unprivileged users to OOM-lockup the system). > > I do not follow. > http://tomoyo.osdn.jp/cgi-bin/lxr/source/mm/oom_kill.c?v=linux-4.6.7#L493 [ 177.722853] a.out invoked oom-killer: gfp_mask=0x24280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), order=0, oom_score_adj=0 [ 177.724956] a.out cpuset=/ mems_allowed=0 [ 177.725735] CPU: 3 PID: 3962 Comm: a.out Not tainted 4.5.0-rc2-next-20160204 #291 (...snipped...) [ 177.802889] [ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name (...snipped...) [ 177.872248] [ 3941] 1000 3941 28880 124 14 3 0 0 bash [ 177.874279] [ 3962] 1000 3962 541717 395780 784 6 0 0 a.out [ 177.876274] [ 3963] 1000 3963 1078 21 7 3 0 1000 a.out [ 177.878261] [ 3964] 1000 3964 1078 21 7 3 0 1000 a.out [ 177.880194] [ 3965] 1000 3965 1078 21 7 3 0 1000 a.out [ 177.882262] Out of memory: Kill process 3963 (a.out) score 998 or sacrifice child [ 177.884129] Killed process 3963 (a.out) total-vm:4312kB, anon-rss:84kB, file-rss:0kB, shmem-rss:0kB [ 177.887100] oom_reaper: reaped process :3963 (a.out) anon-rss:0kB, file-rss:0kB, shmem-rss:0lB [ 179.638399] crond invoked oom-killer: gfp_mask=0x24201ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD), order=0, oom_score_adj=0 [ 179.647708] crond cpuset=/ mems_allowed=0 [ 179.652996] CPU: 3 PID: 742 Comm: crond Not tainted 4.5.0-rc2-next-20160204 #291 (...snipped...) [ 179.771311] [ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name (...snipped...) [ 179.836221] [ 3941] 1000 3941 28880 124 14 3 0 0 bash [ 179.838278] [ 3962] 1000 3962 541717 396308 785 6 0 0 a.out [ 179.840328] [ 3963] 1000 3963 1078 0 7 3 0 -1000 a.out [ 179.842443] [ 3965] 1000 3965 1078 0 7 3 0 1000 a.out [ 179.844557] Out of memory: Kill process 3965 (a.out) score 998 or sacrifice child [ 179.846404] Killed process 3965 (a.out) total-vm:4312kB, anon-rss:0kB, file-rss:0kB, shmem-rss:0kB